Conventionally, there have been techniques of judging a user's state inside a facility using a sensor installed in the facility and automatically activating a device expected to be used in the user's state. Of these techniques, there is an information processing system that accumulates action history information representing a user's action together with a time. The system receives an inquiry from the user, analyzes the content of the inquiry, and narrows down action history information, which is appropriate as a response to the inquiry, based on a keyword included in the inquiry. For example, in a technique disclosed in JP-A No. 2007-011674 (KOKAI), a conversational robot receives from a user an inquiry that includes a keyword designating specific timing, for example, “why did you turn on the television this morning?” inquiring the reason for having activated a device. The conversational robot, which is an information processing system, analyzes the content of the inquiry, narrows down a range of user's action history information based on the facility to refer, and provides a response, for example, “because you took a seat in front of the television this morning” based on the action history information.